Field of the Invention
The present invention relates to mobile communication.
Related Art
3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) that is an advancement of UMTS (Universal Mobile Telecommunication System) is being introduced with 3GPP release 8. In 3GPP LTE, OFDMA (orthogonal frequency division multiple access) is used for downlink, and SC-FDMA (single carrier-frequency division multiple access) is used for uplink. The 3GPP LTE adopts MIMO (multiple input multiple output) having maximum four antennas. Recently, a discussion of 3GPP LTE-A (LTE-Advanced) which is the evolution of the 3GPP LTE is in progress.
As set forth in 3GPP TS 36. 211 V10. 4. 0, the physical channels in 3GPP LTE may be classified into data channels such as PDSCH (physical downlink shared channel) and PUSCH (physical uplink shared channel) and control channels such as PDCCH (physical downlink control channel), PCFICH (physical control format indicator channel), PHICH (physical hybrid-ARQ indicator channel) and PUCCH (physical uplink control channel).
Meanwhile, in recent years, communication, i. e., machine type communication (MTC), occurring between devices or between a device and a server without a human interaction, i. e., a human intervention, is actively under research. The MTC refers to the concept of communication based on an existing wireless communication network used by a machine device instead of a user equipment (UE) used by a user.
Since the MTC has a feature different from that of a normal UE, a service optimized to the MTC may differ from a service optimized to human-to-human communication. In comparison with a current mobile network communication service, the MTC can be characterized as a different market scenario, data communication, less costs and efforts, a potentially great number of MTC apparatuses, wide service areas, low traffic for each MTC apparatus, etc.
Recently, it is considered to extend cell coverage of a BS for an MTC apparatus, and various schemes for extending the cell coverage are under discussion. However, when the cell coverage is extended, if the BS transmits a channel to the MTC apparatus located in the coverage extension region as if transmitting a channel to a normal UE, the MTC apparatus has a difficulty in receiving the channel.
Further, as the MTC apparatus is expected to have low performance in order to supply more MTC apparatuses at a low price, if the BS transmits a PDCCH or a PDSCH to the MTC apparatus located in the coverage extension region as if transmitting a PDCCH or a PDSCH to a normal UE, the MTC apparatus has a difficulty in receiving the PDCCH or the PDSCH.